Consider replacing ace editor with monaco editor

[maxcnunes]

Monaco seems to be a more modern text editor and it has a good typescript support too. I tried it out when I was trying to rewrite the app from scratch and I was able to get SQL keywords auto complete working quite easily https://github.com/sqlectron/sqlectron-gui/pull/553/files#diff-59569bd2b15b3a005a490bab7cd9e24c380a50292dfb049b6edef11495bf1002

We shouldn't try to get everything implemented on the same PR though. This task is just to replace the editor and make sure the existing features still working. Any new feature should have a new ticket created specific for that such as the keywords auto complete feature I mentioned.

This should be done after the new UI implementation #546